Hi STANGERS!!...I got a good one mind puzzler!! I've had my 91 stang LX trunk for about 6ys now I've redone the car from top to bottom in and out front to back.For the past 2 summers if I have half or a full tank of gas and corner hard (road track/street) gas just SPILLS out the filler neck,the tank seems to build up pressure and causes the gas to spill out.The hotter it is the more pressure it makes in the tank.The only modz i have done when this all started was braided fuel lines at the rails and a fuel pump.If anyone ran into this prob or no of any tips or suggestions would be appreciated!!

Things I have tested and trouble shot
1 replaced gas cap with aftermarket & Ford
2 checked for kinks & blockage in lines (none)
3 inspected and tested roll over valve (ok)
4 filler neck is all there
Thankx!!

 

When you say the filler neck is all there, do you mean the filler neck and the gasket at the bottom where the filler neck goes into the tank? My '99 was doing the same thing and the filler neck gasket was torn.